The present invention relates to sewing machines, and particularly to sewing machines including workpiece clamping devices. The invention is especially useful in an automatic sewing machine for automatic sewing of fabric, leather, or the like, and is therefore described below with respect to such an application.
Automatic sewing machines commonly include a machine main frame, a sewing machine head mounted thereon, a carriage movable over the machine main frame, and a workpiece clamp carried by the carriage and movable relative to the sewing machine head to locate the workpiece with respect thereto. Generally in such sewing machines, the workpiece clamp provides only a very limited sewing area presentable to the sewing machine head. This limits the number of operations that can be performed on a workpiece, or the number of workpieces that can be processed during a single series of sewing machine operations, thereby requiring the automatic operation of the sewing machine to be frequently interrupted in order to apply a new clamp or to relocate the workpiece with respect to the clamp.